1. Field of the Invention
The present invention relates to a playback apparatus for reproducing a disk for use as a recording medium, and more particularly to a playback apparatus capable of loading disks of a plurality of types having different diameters.
2. Description of the Related Art
Recently, there has been a remarkable spread of disk playback apparatuses for optically reproducing information recorded in the form of tracks of pits on a disk. Disks to be reproduced by means of the disk playback apparatuses include laser disks (LDs) of 30-cm diameter, compact disks (CDs) of 12- or 18-cm diameter, etc. Accordingly, the disk playback apparatuses of this type are expected to be able to reproduce disks with different diameters.
Disclosed in Jpn. Pat. Appln. KOKAI Publication No. 4-195855, for example, is a disk playback apparatus of the so-called front-loading type which can deal with CDs with different diameters. This conventional apparatus is provided with a disk loading mechanism which comprises rollers and levers, and then has a complicated construction.
Moreover, the disk loading mechanism cannot operate before a disk is inserted for a predetermined distance in a chassis of the playback apparatus. If the disk insertion distance is adjusted substantially to the radius of a disk of 12-cm diameter, therefore, the greater part of an 8-cm disk must be inserted into the chassis in order to actuate the disk loading mechanism. Thus, the 8-cm disk cannot be easily handled during its loading operation.
In ejecting the loaded disk, on the other hand, the disk loading mechanism allows the disk to project from the chassis only for a distance equal to the difference between the insertion distance and the disk diameter. In the case of the 8-cm disk, therefore, the disk ejection distance is so short that the disk cannot be taken out with ease.
If the insertion distance is adjusted to the disk of 8-cm diameter, however, the 12-cm disk cannot be steadily supported by means of the disk loading mechanism when it is loaded. When the 12-cm disk is ejected, moreover, the greater part of its body projects from the chassis, so that it may possibly jump out.